package com.concurrent.atomic;

import com.concurrent.annotations.NotThreadSafe;
import com.concurrent.annotations.ThreadSafe;

import java.util.concurrent.CountDownLatch;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.Semaphore;
import java.util.concurrent.atomic.AtomicInteger;

/**
 * @author: zhouyang
 * @descrpition:
 * @time: 2019-05-03 23:40
 */
@ThreadSafe
public class ConcurrencyTestAtomic {
    //请求总数
    public static int clientTotal = 5000;

    //请求并行的线程数
    public static int threadTotal = 200;

    private static AtomicInteger count = new AtomicInteger(0 );

    public static void main(String[] args) throws Exception{
        ExecutorService executorService = Executors.newCachedThreadPool();
        final Semaphore semaphore = new Semaphore(threadTotal);
        final CountDownLatch countDownLatch = new CountDownLatch(clientTotal);//请求总数
        for(int i=0;i<clientTotal;++i){
            executorService.execute(()->{
                try {
                    semaphore.acquire();
                    add();
                    semaphore.release();
                }catch (Exception e){
                    System.out.println(e);
                }
                countDownLatch.countDown();
            });
        }
        countDownLatch.await();
        executorService.shutdown();
        System.out.println(count.get());
    }

    private static void add(){
        //核心算法 unsafe
        //compare and swapInt
        //CAS的核心 不断比较当前的值是否真实被加上了
        count.getAndIncrement();
    }
}
